Substrate rack and a substrate processing system and method

ABSTRACT

The invention relates to a substrate rack and a substrate processing system for processing substrates in a reaction chamber. The substrate rack may be used for introducing a plurality of substrates in the reaction chamber. The substrate rack may have a plurality of spaced apart substrate holding provisions configured to hold the substrates in a spaced apart relationship. The rack may have an illumination system to irradiate radiation with a range from 100 to 500 nanometers onto a top surface of the substrates.

FIELD

The present invention generally relates to a substrate rack, and asubstrate processing system and method. More particularly, the inventionrelates to a substrate rack constructed for holding a plurality ofsubstrates in a reaction chamber of a substrate processing system duringa substrate processing method. The substrate rack may comprise aplurality of spaced apart substrate holding provisions configured tohold the plurality of substrates in a spaced apart relationship.

BACKGROUND

Furnaces, functioning as reactors, may be used as reaction chambers tocreate fine dimension structures, such as integrated circuits, on asubstrate. Several substrates, such as silicon wafers, may be placed ona substrate holder, such as a substrate rack or boat and moved insidethe reactor. In a subsequent substrate treatment step the substrates maybe heated. Further, reactant gases may be passed over the substrate,causing the deposition of a thin layer of the reactant material orreactants of the gases on the substrate to be treated.

A series of treatment steps on a substrate is called a recipe. If thedeposited layer has the same crystallographic structure as theunderlying silicon substrate, it is called an epitaxial layer. This isalso sometimes called a monocrystalline layer because may have onecrystal structure. Through subsequent deposition, doping, lithography,etch and other processes, these layers are made into integratedcircuits, producing from tens to thousands or even millions ofintegrated devices, depending on the substrate size and the circuits'complexity.

Various process parameters are carefully controlled to ensure the highquality of the resulting layers. One such critical parameter is thesubstrate temperature during each recipe step. During CVD, for example,the deposition gases react within a particular temperature window anddeposit on the substrate. Different temperatures result in differentdeposition rates and quality. Accordingly, it is important to accuratelycontrol the substrate temperature to bring the substrate to the desiredtemperature before the reaction treatment begins. The substrate maycomprise features that are temperature sensitive and therefor thetemperature may be limited to a certain maximum to avoid damage to thosesensitive features.

For certain processes energy may be necessary at the substrate surface.If this energy is provided in the form of heat this may lead tocontradicting requirements in which for productivity, quality and/orreactivity the temperature should be high, while to avoid damage to thefeatures on the substrate the temperature should remain low.

SUMMARY

Accordingly, there may be a need for providing energy to a surface of aplurality of substrates in a reaction chamber.

In accordance with at least one embodiment of the invention there may beprovided a substrate rack. The substrate rack may be constructed forholding a plurality of substrates in a reaction chamber of a substrateprocessing system. The substrate rack may comprise a plurality of spacedapart substrate holding provisions configured to hold the plurality ofsubstrates in a spaced apart relationship. The substrate rack maycomprise an illumination system constructed and arranged to radiateultraviolet radiation with a range from 100 to 500 nanometers onto a topsurface of at least one of the substrates held by the substrate holdingprovisions.

By irradiating the surface of the substrates with ultraviolet radiation,it may be possible to provide energy to the top surface. Theillumination system may be constructed and arranged to radiateultraviolet radiation with a range from 100 to 500, preferably 150 to400, and even more preferably 170 to 300 nanometers. The spaced apartsubstrate holding provisions of the substrate rack may be configured toindependently hold a substrate in a particular orientation.

In accordance with a further embodiment of the invention there may beprovided a substrate processing system comprising:

a reaction chamber constructed and arranged for processing a pluralityof substrates in a rack; and

a rack handler for moving the rack into the reaction chamber. The rackmay comprise an illumination system constructed and arranged to radiateultraviolet radiation with a range from 100 to 500 nanometers from aradiation output surface onto a top surface of at least one of thesubstrates held by the substrate holding provisions. The rack maycomprise a plurality of spaced apart substrate holding provisionsconfigured to hold the plurality of substrates in a spaced apartrelationship.

According to yet a further embodiment there is provided a substrateprocessing method, comprising:

providing a plurality of substrates in a substrate rack comprising aplurality of spaced apart substrate holding provisions configured tohold the plurality of substrates in a spaced apart relationship;

moving the rack with substrates in a reaction chamber; and,

irradiating ultraviolet radiation with a range from 100 to 500nanometers to a top surface of at least one of the substrates held inthe substrate rack from an illumination system provided to the rack.

The method may comprise providing a fluid into the reaction chamber viaan inlet. The fluid may be used to deposit a layer on the substrates.

Alternatively, a fluid may be used to improve the transmissivity of theradiation transmitting or reflecting surface. The fluid may be anoxidizing fluid used to oxidize a layer deposited on the radiationtransmitting or reflecting surface to improve the transmissivity of theradiation transmitting or reflecting surface. The fluid may be anetching fluid so as to etch a layer deposited on the radiationtransmitting or reflecting surface away to improve the transmissivity ofthe radiation transmitting or reflecting surface.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught or suggested herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of certain embodiments having reference to the attachedfigures, the invention not being limited to any particular embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE FIGURES

It will be appreciated that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale. Forexample, the dimensions of some of the elements in the figures may beexaggerated relative to other elements to help improve understanding ofillustrated embodiments of the present disclosure.

FIG. 1 shows a perspective view of the substrate processing system withthe substrate rack according to an embodiment;

FIG. 2 shows a plan top view of the system according to FIG. 1; and

FIGS. 3A, 3B and 3C show a perspective view of a substrate rack withsubstrates that are illuminated with an illumination system according toa first (A) and a second (B) embodiment.

DETAILED DESCRIPTION

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

A substrate processing system with a substrate rack according to anembodiment may be indicated in FIGS. 1 and 2. Said system may beincorporated in an apparatus 1 comprising a housing 2 and may in generalbeing installed partially or completely in a so-called “clean room”.

In addition to housing 2, partitions 3, 4 and 5 may be present, as canbe seen in particular from FIG. 2. Housing 2 may delimit, with partition3, reactor area 21. A substrate handling chamber 22 may be delimitedbetween housing 2 and partitions 3, 4. A cassette handling chamber 23may be delimited between partitions 4 and 5 and housing 2. The apparatus1 may further comprise a cassette introduction portion 33.

Two reactor chambers 6, 7, may be arranged in reactor area 21, howeveralso a single reactor chamber may be used. Said reactor chambers may bepositioned vertically and substrate racks 12 filled with substrates 13,e.g., semiconductor wafers, may be moved into the reactor chambers 6, 7in the vertical direction from below.

The substrate racks 12 may comprise a plurality of spaced apartsubstrate holding provisions configured to hold the plurality ofsubstrates 13 in a spaced apart relationship. The substrate rack 12 maybe supported at the bottom on an insulating plug, which provides a sealwith respect to the reactor chamber 6, 7.

Each reactor chamber 6, 7 may have a rack handler comprising aninsertion arm 14, which is movable in the vertical direction with theaid of a spindle 38, to bring the substrate rack 12 in the reactorchamber. In FIG. 2 it is indicated that there may be two insertion arms14 on both sides of the apparatus. The reactor chamber may be referredto as a furnace and may be provided with a heater to heat thesubstrates.

The rack handler further may comprise a rotary platform 11, providedwith cut-outs 15, arranged in the reaction area 21. Said cut-outs 15 maybe shaped such that, if the cut-outs 15 have been brought into thecorrect position, arm 14 is able to move up and down through thecut-outs. On the other hand, the diameter of the bottom of the substraterack may be such that said diameter is larger than the cut-out 15 in theplatform 11, so that when the arm 14 moves downwards from the positionshown in FIG. 1 the substrate rack 12 may be placed on rotary platform11 and may be removed therefrom again in a reverse operation.

The substrate racks 12 may be fed to both reactor chambers 6 and 7 withthe rack handler. It may be possible to perform a successive treatmenttherein. It may also be possible to allow parallel groups of substrateracks 12 to be treated exclusively by reactor chamber 6 and exclusivelyby reactor chamber 7. Said substrate racks 12 may be provided withsubstrates 13. The system comprises a rotation device for rotating therack 12 with substrates 13 around a vertical axis in the reactionchamber 6, 7 to improve the uniformity of the treatment.

Substrates 13 may be supplied in (transport) cassettes 10 which, fromthe cassette introduction portion 33, may be placed in store 8 through aclosable opening 34 with the aid of arm 31 of the cassette handlingrobot 35. Arm 31 may be provided with a bearing surface 32 which hasdimensions a little smaller than those of the series of cut-outs 26 inrotary platforms 27. A number of such rotary platforms may be providedone above the other in the vertical direction in store 8. Arm 31 may bemovable in the vertical direction with the aid of cassette handlingrobot 35. Arm 31 may be mounted such that said arm is able not only topick up or remove cassettes from or to introduction portion 33 to orfrom store 8, but also to make it possible to move cassettes from or tostore 8 to or from rotary platform 30.

Said rotary platform 30 may be constructed such that on rotation thecassette is placed against partition 4 where an opening 37 has been madeso that, after opening the cassettes, substrates can be taken one by onefrom the cassette concerned with the aid of arm 24 of a substratehandler and can be placed in the substrate rack 12 located in substratehandling chamber 22.

Said substrate rack 12 is supported by a hinged arm 16 being part of therack handler and provided with a bearing surface 17 at the end, thedimensions of which are somewhat smaller than those of cut-outs 15 ofrotary platform 11. Said arm 16 may be able to move with the substraterack through a closable opening in partition 3 by rotation aboutrotation point 18. A closure may be provided in order to be able toclose opening 19 between reaction area 21 and substrate handling chamber22.

An operator or an automated cassette transport system (not shown), mayload store 8 by introducing a number of cassettes on introductionportion 33. Control operations may be done on panel 36. Cassettes 10 maybe transferred from the introduction portion 33 with the aid of arm 31into the storage compartments 9 made for these cassettes in store 8. Bystarting from the lowest position for removing the relevant cassette 10from portion 33 through the opening 34, said cassette can be movedupwards for moving into a higher compartment 9 of the store 8 by thecassette handling robot 35. By rotation of the store 8 it is possible tofill various compartments 9 with cassettes 10.

The cassettes 10 concerned may be removed from the store by arm 31 andplaced on rotary platform 30. The cassettes are rotated on the rotaryplatform 30 and placed with their door against partition 4. The door ofthe cassette may be removed with a door opener. With the aid of arm 24,the substrates may be removed substrate by substrate and placed insubstrate rack 12 placed on swing arm 16 with the substrate handler.

In the interim the rotary platform 11 may be able to move in the reactorarea 21 in an optimum manner with regard to the treatments to be carriedout on the substrates present inside the reactor area 21. Aftersubstrate rack 12 has been filled in the substrate handling chamber 22and may become available to one of the reactor chambers 6, 7, opening19, which was closed up to this time, is opened and said freshly filledsubstrate rack 12 may be placed on rotary platform 11. Said rotaryplatform 11 may then move one position and the filled substrate rack 12may be removed from platform 11 with the help of insertion arm 14 intothe reactor chambers 6, 7. Treated substrates in a finished rack may belowered on said filled platform 11. Said substrates execute a movementcounter to the above to end up in the cassettes.

The substrate rack 12 with the fresh substrate may be fed to reactorchamber 6 or 7 with the insertion arms 14 and may be treated in saidchamber. It may be possible to perform a successive treatment in thereactor chamber 6, 7. As depicted the apparatus may have two reactorchambers 6, 7, but the apparatus may have also one reactor chamber orthree or more reactor chambers without departing from the scope ofinvention.

The treatment may comprise an increase of the temperature of thesubstrates in the substrate rack 12 with a heater. The increasedtemperature may be necessary to get the right reactivity. It istherefore important to accurately control the substrate temperature tobring the substrate to the desired temperature before the treatmentbegins to get the right reactivity and productivity. Further thesubstrate may comprise features that are temperature sensitive andtherefor the temperature may be limited to a certain maximum to avoiddamage to those sensitive features. This may lead to contradictingrequirements in which for reactivity the temperature requirements of thesubstrate may be high while the temperature requirement of the substratemay be limited to avoid damaging the temperature sensitive features onthe substrate.

FIGS. 3A and 3B show a cross-section of a substrate rack 12 with asubstrates 13. The substrate rack 12 may comprise a top plate 41connected with struts 43 to a bottom plate 45. A plurality of spacedapart substrate holding provisions 47 configured to hold the pluralityof substrates 13 in a spaced apart relationship may be provided to thestruts 43. In general 2 to 4 struts may be provided in a rack 12 and 10to 200 substrate holding provisions 47 may be provided to holdsubstrates 13. The rack 12 may be supported by an insulating plug 49which provides a seal with respect to the reactor chamber 6, 7 at thebottom.

The substrate rack 12 may be provided with an illumination systemconstructed and arranged to radiate ultraviolet radiation with a rangefrom 100 to 500 nanometers onto a top surface of at least one of thesubstrates 13 held in the substrate holding provisions 47. Theillumination system may be constructed and arranged to radiateultraviolet radiation with a range from 100 to 500, preferably 150 to400, and even more preferably 170 to 300 nanometers. The substrateholding provisions 47 of the rack 12 may be constructed and arranged tohold the top surface of the at least one of the substrates opposite aradiation output surface of the illumination system so as to radiateultraviolet radiation onto the top surface of the at least one of thesubstrates.

By irradiating the top surface of the substrates with ultravioletradiation it may be possible to provide energy to the top surface forcertain processes. The energy may increase the reactivity on the topsurface. This increase of reactivity may be accomplished while notoverheating the substrate so that temperature sensitive features on thesubstrate may not get damaged. The increase of reactivity may lead to abetter quality of the deposited layer and/or a higher productivity ofthe apparatus. It may also lead to certain processes becoming possibleat a temperature on which before they were not possible because thereactivity was zero.

The illumination system may comprise a plurality of illumination devices51 provided to the rack 12. Each illumination device 51 may havededicated substrate holding provisions 47 on the rack to hold the topsurface of one of the substrates in the radiation of the illuminationdevice.

The energy transfer from an electromagnetic wave (like UV) unto the topsurface of the substrate is proportional to the cosines of the anglebetween an axis perpendicular to the top surface of the substrate andthe direction of the radiation. The illumination device may therefore beconstructed and arranged to direct the radiation in a direction within0-60 degrees, preferably 0-45 degrees, more preferably 0-30 degrees andmost preferably 0-15 degrees of an axis perpendicular to the top surfaceof the substrate on the top surface of the substrate. Further, it may bedifficult to direct direction to deep trenches that may be formed in themicrostructures on the top surface of the substrate. Radiation in adirection with smaller angles with an axis perpendicular to the topsurface of the substrate may increase the in coupling of the radiationinto deep trenches.

The dedicated substrate holding provisions 47 provided to the rack 12may be configured to hold one substrate in between two illuminationdevices. The illumination device 51 may have a substantially plate shapewith a top and a back surface. The back surface may comprise theradiation output surface. The illumination device 51 may havesubstantially the same size as the substrate 13 in directions parallelto the substrate surface.

FIG. 3C depicts an enlargement of the illumination device 51 of FIG. 3A.The illumination device 51 which may be provided with illuminationsources 53, 55. Some illumination sources 53 may irradiate ultravioletradiation onto the top surface of at least one of the substrates in thesubstrate rack 12. The illumination sources 53 comprise a first lightemitting diode for irradiating ultraviolet radiation within a range from100 to 500, preferably 150 to 400, and even more preferably 170 to 300nanometers. Other illumination sources 55 comprise a second lightemitting diode for irradiating infrared radiation within a range from700 nanometers to 1 millimeter to heat the substrate.

In FIG. 3B the illumination device 51 is provided with illuminationsources 53 only comprising a first light emitting diode for irradiatingultraviolet radiation within a range from 100 to 500 nanometers. Theheating function in FIG. 3B is accomplished by the heater provided withheating coils 51. Beside the heating function, FIG. 3A and FIG. 3B areidentical and function in conjunctions with each other so that FIG. 3Bfunctions as the lower part of the FIG. 3A and the other way around.

The rack 12 may be provided with an electrical power connection 57connectable to a power source V. The rack could, for example, have apower connector. The power connector may have a plug and socketconnection. The illumination system may be active and constructed andarranged to generate radiation from the electrical power and direct theradiation to the substrates. The illumination devices 51 may comprise agas discharge lamp or a light emitting diode to generate radiation fromthe electrical power.

Gas discharge lamps generate radiation by having an electric dischargebetween two electrodes through an ionized gas, e.g., a plasma in a tube.Such lamps may use a noble gas such as argon, neon, krypton, and xenonor a mixture thereof and additionally even may use mercury, sodium, andmetal halides in the mixture in the tube. The electrons may be forced toleave atoms of the gas near an anode by the electric field appliedbetween the two electrodes from which only one 45 is depicted, leavingthese atoms positively ionized. Free electrons flow to the anode, whilethe cations flow to the cathode. The ions may collide with neutral gasatoms, which transfer their electrons to the ions. The atoms, havinglost an electron during the collisions, ionize and speed toward thecathode while the ions, having gained an electron during the collisions,return to a lower energy state while releasing energy in the form ofradiation which is emitted in the direction of the substrate top surfaceof the substrate to transfer its energy into the top surface.

The rack 12 may be provided with a passive illumination deviceconstructed and arranged to direct radiation from outside the rack tothe substrates. The active components of the illumination source may beprovided outside the reaction chamber in the apparatus and direct theradiation to the passive illumination device provided in the rack. Thepassive components in the reaction chamber may be less sensitive to thehot and reactive environment in the reaction chamber than the activecomponents.

The passive illumination device may comprise an optical wave guide toguide the radiation to the substrates. The optical wave guide may be anoptical fiber. The optical wave guide may be hollow.

The passive illumination device may be provided with radiationreflecting surface to direct the ultraviolet radiation to thesubstrates. The radiation reflecting surface may comprise a mirror toredirect the radiation to the substrates. The radiation reflectingsurface may be made of glass, steel, aluminum or polytetrafluoroethylene(PTFE) to reflect ultraviolet radiation. The radiation reflectingsurface may have an upside down cone shape to reflect ultravioletradiation from the side of the rack downwards to the substrate surface.The radiation reflecting surface may comprise a scatter plate to scatterthe radiation to the substrates.

The rack 12 may be provided with a gas supply system for providing a gasflow on a radiation transmitting or reflecting surface. In this waydeposition of contamination on the radiation transmitting or reflectingsurface may be circumvented. The illumination system may comprisemultiple parts to irradiate ultraviolet radiation to the substrates inthe substrate rack from multiple sides.

The illumination system for illuminating the substrate surface may havea power of between 5 W and 100 kW, preferably 300 W and 20 kW and evenmore preferably between 1 and 10 kW. The illumination devices forilluminating the substrate surface may have a power of between 0.05 and150 W, preferably 1 W and 60 W and even more preferably between 4 and 50W. The illumination system may have an efficiency of between 50 and 90%in the conversion of electrical energy to ultraviolet radiation. Thesubstrate surface may receive a power between 0.1 and 200 milliwatt(mW)/cm², preferably between 1 and 100 mw/cm² and even more preferablybetween 5 and 80 mW/cm².

The rack 12 may have a length between 50 and 200 cm and may be between20 and 50 cm, preferably around 30 cm wide. The rack 12 may have amaximum of between 20 and 120, preferably between 40 and 80 spaced apartsubstrate holding provisions along the struts for holding an equalamount of substrates. The rack 12 may be provided with between 20 and130, preferably between 40 and 80 illumination devices 51. The distancebetween the substrates 13 and the illumination devices 51 in the rack 12may be between 4 to 20, preferably 5 to 10 mm.

The apparatus may be provided with at least one fluid inlet 59. Thefluid inlet 59 may be embodied as an injector within the reactionchamber for providing a fluid into the reaction chamber. A purge orprocessing gas may be provided through the inlet 59. The apparatus maybe provided with a fluid system comprising a control system forcontrolling a valve for providing the fluid such as a processing orpurge gas in the reaction chamber via the inlet. The fluid may bereceived from a fluid storage or a gas line.

The control system and the valve may be constructed and arranged toprocess substrates. More particularly the control system and the valvemay be constructed and arranged to perform an atomic layer deposition(ALD) or chemical vapor deposition (CVD) cycle on the substrate with afirst and/or second precursor stored in a fluid storage. The apparatusmay be provided with a fluid outlet 61 to remove gases from the reactionchamber 6, 7. The ultraviolet radiation can be used to deposit ordensify, atomic (ALD) layers, chemical vapor deposition (CVD) layers orother layers.

When layers of, for example, silicon or silicon nitride are deposited ina reaction chamber 6, 7, the efficiency of the ultraviolet radiationsystem may be reduced by absorption when a thickness of depositedmaterial is adding up on top of the radiation transmitting surface.Purging the radiation transmitting surfaces may be alleviating thisissue to some extent.

A complementary periodical in situ clean with etch gases may be arequired to clean the radiation transmitting or reflecting surface ofthe illumination devices 51. The apparatus may comprise an etchingsystem. The etching system may comprise a fluid storage, a controlsystem and a valve. The control system may be provided with a programwhen run on the control system to improve the transmissivity of theradiation transmitting or reflecting surface after a layer is depositedon the radiation transmitting or reflecting surface.

An etching fluid may be stored in the fluid storage of the etchingsystem. The control system may be controlling a valve for providing theetching fluid in the reaction chamber 6, 7 via the inlet 59. The controlsystem may control the valve to provide the etching fluent i.e., etchantin the reaction chamber, so as to etch a layer deposited on theradiation transmitting or reflecting surface away to improve thetransmissivity of the surface.

The etching fluid may be chloride (Cl2), boriumchloride (BCl3),hydrogenchloride (HCl), tetrafluoromethane (CF4), nitrogentrifluoride(NF3), hydrogenbromide (HBr), sulfur hexafluoride (SF6), or an ashingcomponent created by ultraviolet radiation in combination with anhydrogen or oxygen comprising gas such as hydrogen or oxygen. Theperiodical in situ clean with etch gases may also be used as analternative for purging the radiation transmitting or reflectingsurfaces which may simplify the design of the apparatus.

The radiation transmitting surface or reflecting surface may also bemade transmissive or reflective for the illumination radiation again byperiodically converting the silicon or silicon nitride layers intosilicon oxide by a thermal treatment in an oxidizing environment. Theapparatus may comprise a conversion system. The conversion system maycomprise the fluid storage, the control system and the valve. Thecontrol system may be provided with a program when run on the controlsystem to improve the transmissivity of the radiation transmitting orreflecting surface after a layer is deposited on the radiationtransmitting or reflecting surface.

An oxygen comprising fluid, such as, for example, oxygen (O₂), ozone(O₃), peroxide (H₂O₂), water (H₂O), or nitrous oxide (N₂O), may for thispurpose be stored in the fluid storage. The control system may becontrolling a valve for providing the oxidizing fluid in the reactionchamber 6, 7 via the inlet 59 from the fluid storage and controllingheating of the reaction chamber. After conversion of the silicon orsilicon nitride layers into silicon oxide the silicon oxide may transmitthe UV and no in situ clean may be required. The periodical in situconversion with oxidizing gas may also be used as an alternative forpurging the radiation transmitting or reflecting surfaces which maysimplify the design of the apparatus.

The substrate 13 may be positioned in the substrate rack 12 having threestruts 43 comprising a plurality of spaced apart substrate holdingprovisions 47 configured to hold the plurality of substrates 13 in aspaced apart relationship. The struts 43 may be elongated and extend ina direction substantially perpendicular to the substrate surface, e.g.,in a vertical direction. The plurality of substrates may be positionedparallel in the substrate rack 12. The top plate 41 and the bottom plate45 may extend parallel to the substrates in a horizontal direction.

Alternatively, a rack 12 may be filled with substrates to be processedalternating with removable illumination devices 51 which are alsopositioned in the rack. The removable illumination devices could, forexample, have their own independent power supply or a power connector.The independent power supply could be a working with a chargeablebattery, or an RF receiver. The power connector may have a plug andsocket connection with the rack or a part of the apparatus. Thesubstrate handler may be used to fill the rack 12 with the substrates 13to be processed alternating with the removable illumination devices 51.The removable illumination devices could be switched on after the rackis moved into the reactor. The removable illumination devices 51 may beremoved from the rack and cleaned after the rack is moved out of thereaction chamber. Removable illumination devices create a very versatilesystem.

The particular implementations shown and described are illustrative ofthe invention and its best mode and are not intended to otherwise limitthe scope of the aspects and implementations in any way. Indeed, for thesake of brevity, conventional manufacturing, connection, preparation,and other functional aspects of the system may not be described indetail. Furthermore, the connecting lines shown in the various figuresare intended to represent exemplary functional relationships and/orphysical couplings between the various elements. Many alternative oradditional functional relationship or physical connections may bepresent in the practical system, and/or may be absent in someembodiments.

It is to be understood that the configurations and/or approachesdescribed herein are exemplary in nature, and that these specificembodiments or examples are not to be considered in a limiting sense,because numerous variations are possible. The specific routines ormethods described herein may represent one or more of any number ofprocessing strategies. Thus, the various acts illustrated may beperformed in the sequence illustrated, in other sequences, or omitted insome cases.

The subject matter of the present disclosure includes all novel andnonobvious combinations and sub combinations of the various processes,systems, and configurations, and other features, functions, acts, and/orproperties disclosed herein, as well as any and all equivalents thereof.

1. A substrate rack constructed for holding a plurality of substrates ina reaction chamber of a substrate processing system, the substrate rackcomprising a plurality of spaced apart substrate holding provisionsconfigured to hold the plurality of substrates in a spaced apartrelationship, wherein the substrate rack comprises an illuminationsystem constructed and arranged to radiate ultraviolet radiation with arange from 100 to 500 nanometers onto a top surface of at least one ofthe substrates held in the substrate holding provisions.
 2. The rackaccording to claim 1, wherein the substrate holding provisions of therack are constructed and arranged to hold the top surface of the atleast one of the substrates opposite a radiation output surface of theillumination system so as to radiate ultraviolet radiation onto the topsurface of the at least one of the substrates.
 3. The rack according toclaim 1, wherein the illumination system comprises a plurality ofillumination devices provided to the rack and each illumination devicehas dedicated substrate holding provisions on the rack to hold the topsurface of one of the substrates in the radiation of the illuminationdevice.
 4. The rack according to claim 3, wherein the dedicatedsubstrate holding provisions on the rack are configured to hold onesubstrate in between two illumination devices.
 5. The rack according toclaim 3, wherein the illumination device comprises a substantially plateshape with a top and a back surface and the back surface comprises aradiation output surface.
 6. The rack according to claim 3, wherein theillumination device has substantially the same size as the substrate indirections parallel to the top surface.
 7. The rack according to claim3, wherein the illumination device is provided with illumination sourcesirradiating ultraviolet radiation onto the top surface of at least oneof the substrates in the substrate rack.
 8. The rack according to claim7, wherein the illumination device comprises a first light emittingdiode for irradiating ultraviolet radiation within a range from 100 to500 nanometers.
 9. The rack according to claim 7, wherein theillumination device comprise a second light emitting diode forirradiating infrared radiation within a range from 700 nanometers to 1millimeter to heat the substrate.
 10. The rack according to claim 1,wherein the illumination system is passive and is constructed andarranged to direct radiation from outside the rack to the substrates.11. The rack according to claim 1, wherein the illumination systemcomprises an optical wave guide to guide the radiation to thesubstrates.
 12. The rack according to claim 11 wherein the optical waveguide is an optical fiber.
 13. The rack according to claim 1, whereinthe illumination system is provided with radiation reflecting surfacesto direct the ultraviolet radiation to the substrates.
 14. The rackaccording to claim 13, wherein the radiation reflecting surfacescomprises a material selected from the group of material comprisingglass, steel, aluminum or polytetrafluoroethylene (PTFE) to direct theradiation to the substrates.
 15. The rack according to claim 13, whereinthe radiation reflecting surfaces comprises a scatter plate to scatterthe radiation to the substrates.
 16. The rack according to claim 1,wherein the illumination system is constructed and arranged to directthe radiation in a direction within 0-45 degrees of an axisperpendicular to the top surface of the at least one of the substrates.17. The rack according to claim 1, wherein the rack is provided with anelectrical power connection and the illumination system is active andconstructed and arranged to generate radiation from the electrical powerand direct the radiation to the substrates.
 18. The rack according toclaim 17, wherein the illumination system comprises a discharge lamp.19. The rack according to claim 1, wherein the rack is provided with agas supply system for providing a gas flow on a radiation transmittingor reflecting surface.
 20. The rack according to claim 2, wherein theillumination system comprises multiple parts to irradiate ultravioletradiation to the substrates in the substrate rack from multiple sides.21. The rack according to claim 1, wherein the rack is constructed andarranged for movement in a reaction chamber.
 22. A substrate processingsystem comprising: a reaction chamber constructed an arranged to processa plurality of substrates in a rack according to claim 1; and a rackhandler constructed and arranged to move the rack into the reactionchamber.
 23. The substrate processing system according to claim 22,wherein the system comprises a rotation device for rotating the rackwith substrates around a vertical axis in the reaction chamber.
 24. Thesubstrate processing system according to claim 22, wherein the reactionchamber is limited by a process tube and the system comprises a UVradiation system constructed and arranged to irradiate the ultravioletradiation through the process tube into the reaction chamber to theillumination system of the rack and the illumination system is passiveand is constructed and arranged to direct radiation from outside therack to the substrates.
 25. The substrate processing system according toclaim 22, wherein the rack is provided with an electrical powerconnection which is electrically connected to the rest of the substrateprocessing system to supply energy to the rack.
 26. A substrateprocessing method, comprising: providing a plurality of substrates in asubstrate rack comprising a plurality of spaced apart substrate holdingprovisions configured to hold the plurality of substrates in a spacedapart relationship; moving the rack with substrates in a reactionchamber; and, irradiating ultraviolet radiation with a range from 100 to500 nanometers to a top surface of at least one of the substrates heldin the substrate rack from an illumination system provided to the rack.27. The substrate processing method according to claim 26, whereinirradiating ultraviolet radiation to the substrates in the substraterack comprises directing the ultraviolet radiation to the substrates viaa radiation transmitting or reflecting surface.
 28. The substrateprocessing method according to claim 26, wherein the method comprisesproviding a fluid into the reaction chamber via an inlet.
 29. Thesubstrate processing method according to claim 28, wherein the methodcomprises providing a fluid with a precursor into the reaction chambervia the inlet to deposit a layer on the substrates.
 30. The substrateprocessing method according to claim 28, wherein the method comprisesproviding an oxidizing fluid in the reaction chamber so as to oxidize alayer deposited on the radiation transmitting or reflecting surface toimprove the transmissivity of the radiation transmitting or reflectingsurface.
 31. The substrate processing method according to claim 28,wherein the method comprises providing an etching fluid in the reactionchamber so as to etch a layer deposited on the radiation transmitting orreflecting surface away to improve the transmissivity of the radiationtransmitting or reflecting surface.